This invention relates to image-receiving elements for use in diffusion transfer photographic processes and in the production of laminated information-bearing documents such as identification (ID) cards. More particularly, it relates to such image-receiving elements including a predetermined preprinted security pattern and to the securement of laminated documents prepared therefrom.
Laminated docments (such as ID cards) essentially comprise a card or other document usually containing information relating to the bearer, and frequently will include a portion of the information in the form of a photograph of the bearer. Normally, the card or other document will be protected by a plastic sheet material such as by lamination of a protective plastic sheet material to the document, or, as is more usually the case, by lamination of the document between a pair of plastic sheets. Laminated documents such as ID cards have many recognized applications. For example, they are used to establish a person's authorization to conduct certain activities (e.g., driver's licenses) or their right of access to certain areas (e.g., employee passes) or their authorization to engage in credit or other business transactions (e.g., credit cards). In view of the widespread use of laminated documents, especially in commercial transactions, such as cashing checks, credit purchases and the like, it is important that persons relying on such documents as a means of verifying the identity of the bearer have maximum assurance that the ID card or other document has not been altered and that the document is not a counterfeit.
Considerable effort and ingenuity has been employed in the art of security documents to provide the desired degree of assurance. For example, specialized adhesive systems and lamination techniques have been developed to prevent or discourage alteration of ID cards. These systems and techniques are designed to acheive a high degree of bonding efficiency between a surface of the card and a plastic sheet bonded thereto. Certain adhesive systems, for example, can provide what is known in the art as a "security seal", which is best understood by reference to what occurs if an attempt is made to remove the protective plastic sheet material from the surface of the card. If a "security seal" exists, all or at least portions of the adhered surface will be removed from the card together with the plastic sheet. Under such circumstances, removal of portions of the information-bearing surface of the card evidences the attempted removal of the protective sheet; and destruction or disfiguring of the information-bearing surface renders the card unuseable for alteration purposes. Adhesives and methods for providing "security seals" in ID cards are described, for example, in U.S. Pat. No. 3,582,439 (issued June 1, 1971 to J. F. Thomas); U.S. Pat. No. 3,614,839 (issued Oct. 26, 1971 to J. F. Thomas); U.S. Pat. No. 4,101,701 (issued July 18, 1978 to M. E. Gordon); and U.S. Pat. No. 4,115,618 (issued Sept. 19, 1978 to W. T. MacLeish et al.)
Various other features have been embodied into ID cards as means for rendering the card tamper-proof or for verifying authorized issuance or authenticity of the card. The best known verification feature takes the form of the signature of the bearer of the card or of the issuing authority. Others include fluorescent materials, printed patterns, indicia and designs, and printed guilloche patterns customarily used on securities and banknotes, such as described in U.S. Pat. No. 3,279,826 (issued Oct. 18, 1966 to F. J. Rudershausen et al.); U.S. Pat. No. 3,417,497 (issued Dec. 24, 1968 to D. F. Hannon); U.S. Pat. No. 3,758,970 (issued Sept. 18, 1983 to M. Annenberg); U.S. Pat. No. 4,097,279 (issued June 27, 1978 to E. N. Whitehead); U.S. Pat. No. 4,232,079 (issued Nov. 4, 1980 to T. Raphael, et al.); and British Patent Specification No. 1427581 (published Mar. 10, 1976).
Commercial "instant" or "on-the-spot" ID card issuance systems have been employed to provide an ID card for an intended bearer for immediate use. Many such systems are based on cards or documents comprising color photographs from diffusion transfer photographic film units. Diffusion transfer photographic film units useful for this purposes are commercially available from Polaroid Corporation under the trademark designation Polacolor 2. Essentially, such film units comprise a photosensitive element that can provide an imagewise distribution of diffusible image-dye providing materials, after exposure and after application of a processing composition between the photoexposed element and a superposed image-receiving element. Once development is complete, the photosensitive and image-receiving elements are peeled apart and the image is viewed in the image-receiving layer of the image-receiving element. Typically, the diffusion transfer print will be a diffusion transfer processed recordation of the likeness of the intended bearer and certain personal information relating to the bearer and will be the result of simultaneously photographing the bearer and a data card containing such personal information. The print will then be protected by lamination of a plastic sheet over the diffusion transfer photographic print or, as discussed above, by laminating the photograph between a pouch comprising front and back protective sheets.
The integration into a laminated document of a feature designed to enhance the security of the document against alteration and/or couterfeiting can be accomplished in number of ways. For example, a verification pattern in pigment material can be integrated into the adhesive bond existing between the photograph and the protective plastic sheet, as described in the aforementioned U.S. Pat. No. 4,232,079. Incorporation of indicia or other features into a diffusion transfer image-receiving element may, however, present difficulties from the standpoint of production of such an element or the security of a laminated document prepared therefrom. Typically, the image-receiving element employed in a diffusion transfer film unit useful for the production of color ID photographs will comprise a support carrying a polymeric acid layer, a time modulating (or spacer) layer and an image-receiving layer. The incorporation into such an image-receiving element of, for example, a pattern of fine-line security printing, such as is commonly used in banknote paper, stock certificates and the like, and which by the intricate nature of the pattern discourages reproduction and serves as a security feature for documents, may present certain difficulties. The presence of a printed pattern, for example, may prevent adequate adhesion between the layers of the image-receiving element and may contribute to undesired delamination upon attempts to remove the document from the laminate.
In the case of an image-receiving element comprised, for example, of a support carrying, in order, a polymeric acid layer, a time modulating layer and an image-receiving layer, it may be desirable from the standpoint of security to incorporate a fine-line security pattern by printing the desired pattern onto the time modulating layer (prior to application of the superposed image-receiving layer). Upon production of a diffusion transfer photograph from such element, the informational content of the image-bearing layer may then be viewed along with the preprinted fine-line security pattern, which typically will be a unique and self-identifiable pattern preselected by the issuing authority. The resulting ID photograph, as mentioned previously, may be secured by laminating the photograph between a pouch of front and rear polymeric sheet members.
It will be appreciated that it would be extremely disadvantageous if one could alter such a document without evidence of tampering or if the components of the document could be delaminated or parts thereof be reused for the fabrication of an altered or counterfeit document. For example, it would be undesirable if a delamination were to occur in such a manner that the protective cover sheet and image-bearing layer could be separated from the document leaving an element comprised of the support carrying the polymeric acid layer, the time-modulating layers and the unique printed pattern intact thereon. This would be unacceptable for the reason that the remaining element carrying the unique printed pattern could be re-used for the fabrication of another laminated document having the appearance of a validly issued document. Such an occurrence would thwart to a considerable degree the security afforded by the fine-line printed pattern.